Fiber



Patented Aug. 1 5, 1939 j 7 UNITED STATES PATENT OFFICE 2,169,690 r'mnn Stephen P. Gould and Earle 0. Whittier, Washington, D. 0.; dedicated to the free use of the People in the territory of the United States No Drawing. Application May 28, 19st,

, Serial No. 210,789 2 Claims.. (CI. 18-54) (Granted under the act of March .3, 1883, as amended April 30, 1928;3'10 Q. G. 757) 'This application is made under act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed, if patented, may be manufactured and used by 5 or for the Government of the" United States of America for governmental purposes without the payment to us of any royalty thereon.

We hereby dedicate the invention herein described to the free use of the people in the territory of the United States to take effect on the granting of a patent to us.

Our invention deals with a precipitating bath useful forprecipitating, strengthening, and ren-' ydering water-.resistent, fibers composed essen- I tially of casein.

v The object of our invention is to produce a bath containing a soluble calcium (or other alka-' line earth) compound which will react with the fibers to increase their strength and water-resist-' go ance, and to minimize loss of calcium from. the fibers while-they are in the precipitating bath.

Sulfuric acid is commonly used in said baths,

but calcium cannot be incorporated with it because of the formation of insoluble calcium sul- 25 fate. Hydrochloric acid seems to exert a weakening efiecton the fibers. However, we found that a combination of phosphoric acid and manual-'- cium phosphate tcamaommoi worked well since the calcium was kept in soluble form in the so a The following example illustrates a satisfactory procedure. Proportions are given in parts.

-7; "Spinning solution Casein f 24 .Wat'er 208.8 Sodium lauryl sulfate .4'.8 40 Calcium hydroxide 2.4

Water 60.:

The 24' parts of casein are soaked in thc 208 .8' pts.;of water for 15-30 minutes and the'sodium lauryl sulfate is then stirred into-the mixture Inthe meantime, a of the 3.4 pm. of

- calcium hydroxide and the 60 p't's;--of water should be prepared. This is next stirred" mechanically into the casein mixture until a smooth dispersion isobtained. This solution requires careful filtration. 7 n

Precipitating bath Phosphoric acid 5 Monocalcium phosphate [CaHdPOO-aHzOL- i0 Formaldehyde 5 Dextroser W Water 60 are, of course, applicable. That is, the spinning solution is extruded intothe precipitating bath, through any type of spinnerette normally used in the rayon industry.

Having thus described our invention what we claim for Letters Patent is: y We claim: 1. A process for producing casein fibers of enhanced strength and water resistance, which includes subjecting an alkaline solution comprising casein, in the form of fine streams, to the action of an acid bath jcomprising a solution-oi phosphoric acid and an alkaline earth phosphate.

2. A process for producing casein fibers of enhanced strength and water resistance, which includes subjecting an alkaline solution compris- 40 ing casein, in the form of fine streams, to the action of anjacid bath comprising a solution of phosphoric acid and monocalcium phosphate. STEPHENP.GOULD.

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